Table of Contents
In Lesson 5 I discussed various parameters needed to construct a resistance training program. In Lesson 4 I discussed how progressive overload, where you continue to provide the body a challenging stimulus over time as it adapts to prior stimuli, is needed to make continued progress. Initially you can simply lift more weight each session but this eventually yields diminishing returns. Additionally, there may be days where you feel weaker for whatever reason (ie, poor sleep, life stress, etc); this is where an autoregulated approach can prove helpful. Separately, in order to train multiple fitness attributes many people utilize a periodization scheme. Both of these strategies provide options for more variety on a daily, weekly, and monthly basis. I will discuss these topics in this lesson.
Linear progression – good for a complete beginner
As a complete beginner, or as someone who is coming back from a long break, linear progression works well. The idea here is to add weight or reps to each set over successive sessions as neuromuscular adaptations occur that generate increased strength.
Note: Many people refer to this initial phase of rapid strength gains as “noob gains”. Even a highly trained individual who embarks on a new training style (ie, a football player beginning to perform Romanian deadlifts for the first time) can undergo “noob gains” as motor patterns and neuromuscular adaptations are movement-specific.
This beginner phase is an excellent time to focus primarily on good form with various exercises. Bad habits developed in this phase are harder to break in the future. Initially, most beginners can lift more weight when their technique breaks down, but this does not mean they are getting stronger. If this occurs it is better to go back to the lighter weight and slowly build up so you can maintain good technique throughout a set.
Tip: Good technique can look very different in different individuals. This is due to variations in body structure (ie, height and limb length). Additionally, when lifting heavier weights the body’s movement through space may change to maintain a consistent center of gravity. Rather than think your form has to look exactly like someone else’s, it is better to understand the general principles for any given exercise and make sure your technique meets those principles.
Once you can perform exercises with good form, the primary way to judge if your form is breaking down is to see if it changes throughout a set. If you do a 10 rep set and reps 8-10 look different from reps 1-7, then you have experienced form breakdown. However, a common pitfall for beginners is that they are actually strong enough to do all 10 reps with good form but they lack the focus and technical mastery to maintain good form as fatigue sets in. This is where consistency comes in to play; if you stay consistent then after performing enough reps with good form it becomes second-nature and it is easier to maintain good form when fatigued.
So how can you know if your form is changing throughout a set? Take videos of your sets. This is incredibly useful; watch the video after your set and make indicated modifications.
Of note, I discuss appropriate exercise technique in Lessons 9-12.
So what will linear progression look like in practice? The below box has an example.
Example: Jason is a complete beginner starting to workout for the first time. He is doing a full body workout 3 times a week. Each session he is doing 4 exercises:
- barbell back squat, 3 sets of 10 reps (3×10)
- barbell bench press, 4×10
- deadlift, 3×10
- lat pulldown, 4×10
As squats and deadlifts somewhat overlap with the muscles they work, this yields ≥10 sets per week for the legs and 12 sets per week for the muscles primarily worked by the bench press & lat pulldown.
I’ve talked previously about RPE, RIR, and avoiding failure. Jason does want to avoid failure. However, as a complete beginner he is not concerned about RPE and RIR right now, he just wants to practice good form while the noob gains occur. Thus, he starts with 45 pounds (this is the weight of a typical empty barbell, though this can vary). Assuming he is able to complete 3×10 on squats with 45 pounds, the next workout he adds 5 pounds to each set. He then repeats the 3×10 and keeps adding 5 pounds each session.
With this approach he gets lots of rep work with lighter weights initially; at first this is not challenging but it is useful as he is developing consistent technique. He is also developing the habit of going to the gym and doing his workouts consistently. Eventually the weights will start to feel heavier; at this point he is learning to push himself when things become hard. He is videotaping 1 set each session to ensure his form remains good. When he can no longer complete 3×10 because the weight is too heavy, then he knows it is time to change the program in some way.
What if Jason cannot do 3×10 the first session, or what if this is pretty heavy and thus he isn’t getting to practice with lighter weights to develop good form? In that case it will be important to try to figure out why 45 pounds feels heavy. If it is a technique issue then he should take a video of himself to help identify and address the problem. If it is legitimately a strength issue then changing exercises can be helpful. Some example substitutions:
- instead of barbell back squats, choose goblet squats with a 5 pound dumbbell
- instead of barbell bench presses, choose dumbbell bench presses with 5 pound dumbbells
If 5 pounds feels light but then 10 or 15 pounds feels heavy, then instead of doing 3×10 each session you can start with 3×10, then move up to 3×15, then 3×20, and consider going all the way to say 3×30 with the 5 pound dumbbells prior to moving up to the 10 pound dumbbells.
The above example shows a viable method to use to start resistance training. Different exercises and progression schemes are also feasible. The important idea is to pick a handful of exercises, start light, work up slowly, focus on maintaining good technique, and develop consistency. I discuss example resistance training programs in more detail in Lessons 13 and 14.
How to account for delayed-onset muscular soreness (“DOMS”)
As discussed in Lesson 4, DOMS generally peaks 24-48 hours after resistance training. However, if you really push it DOMS may peak 48-72 hours after resistance training. Thus, if you planned to do the beginner workout above on Monday, Wednesday, and Friday, then you may be sore for the Wednesday & Friday workouts. Thankfully, if you start with very light weight (as advocated above) then soreness is unlikely to be significant. DOMS is typically most prevalent the first few weeks of training; starting light and building up slowly largely mitigates this.
That said, it is completely fine to train while mildly sore. When DOMS is more significant it may be better to take an additional rest day as significant soreness can negative impact your strength and technique. If at any point when warming up it seems the soreness will impede your lifting, options include adding a rest day, performing cardiovascular activity, or focusing on body parts that are not sore.
Note: It is important to realize that DOMS is NOT necessary for skeletal muscle hypertrophy or strength gains in general.(Damas, 2018) Soreness typically decreases after training for several weeks. Thus, there is actually no correlation between DOMS and overall results. This is one situation where “No pain, no gain” is completely inaccurate. Tons of great progress is possible with at most minimal soreness and no pain. If you move up in weights gradually and are not feeling sore this is not a sign that anything is wrong and you should not consider altering your program due to this.
Once linear progression comes to an end it is generally helpful to employ an autoregulated approach. This was briefly described in Lesson 4; I will elaborate on some of the common methods here. The basic idea is to allow how your body feels on a given day to help guide performance.
Various autoregulated approaches have been employed since at least the 1940s, and there is still not a unanimous consensus about how to best utilize these.(Greig, 2020) Many different methods are available to determine your overall fatigue and readiness to perform. These include biochemical markers, psychometric surveys, readiness scales, jump height or grip strength, among others; you can use these various metrics to help determine starting loads for an exercise or even what to do in a specific training session.(Helms, 2020) However, these approaches are not commonly utilized (with a possible exception in the case of higher level athletes) and they are certainly not necessary.
More commonly, people use autoregulation within sessions to help determine specific loads and stopping points for sets. This allows real time feedback to guide individual workouts. The three primary means by which this is done typically include rating of perceived exertion (“RPE”), repetitions in reserve (“RIR”), and/or velocity-based training (“VBT”). VBT is not a viable option for most beginners but for completeness I discuss it briefly below.
Note: There have been several reviews recently that evaluate the merit of autoregulated approaches:
- Authors of a 2021 systematic review (“SR”) comparing different autoregulation approaches did not find many well-designed studies.(Larsen, 2021) However, the evidence indicated RIR-based RPE (described below) is more effective than non-autoregulated percentage-based protocols. Additionally, they found group-based VBT (described below) may be even more effective than RIR-based RPE.
- A separate 2021 systematic review and meta-analysis (“SR/MA”) comparing autoregulated approaches to non-autoregulated percentage-based protocols utilized with athletes found an overall benefit to autoregulated approaches as well.(Zhang, 2021)
- A 2022 SR/MA only including studies with individuals who have previous experience with resistance training, in contrast, did not find a benefit of using RIR-based RPE vs non-autoregulated progression schemes, though a benefit was seen with VBT approaches.(Hickmott, 2022)
Thus, it is not completely clear how beneficial autoregulated approaches will be for any given individual. You are more than welcome to learn about them below and to consider implementing them in your own training when linear progression is no longer occurring, but you can alternatively consider incorporating training routines with planned variation. This is discussed further in the periodization section at the bottom of this lesson.
Daily adjustable progressive resistive exercise (“DAPRE”)
This approach was initially developed in 1979 for rehabilitation settings; an expanded version in 2000 included a 3RM (meaning 3 repetition maximum), 6RM, and 10RM to focus on power, strength, and hypertrophy.(Greig, 2020) This is done with 4 sets as described in the following table:
This is a fairly rigid protocol and requires training to failure on 2 successive sets. For these reasons this has fallen out of favor and is not typically utilized. However, there can be merit for those who lack the ability and experience to employ other autoregulated approaches effectively.(Zhang, 2021)
Note: A variation of this scheme can be used where one stops short of failure. Do as many reps as possible on a final set but stop 1-2 reps shy of failure. Then adjust the load in the next training session based on how many reps you completed. Alternatively, stop all sets short of failure until the final set and take this last set to failure. Then, based on how many reps you perform, adjust the weight for the next session. This is a viable strategy and is commonly utilized in various training programs.
Flexible nonlinear periodization (“FNLP”)
With this approach you choose your specific workout protocol for the day based on your perceived performance capability for that specific session.(Greig, 2020) In a 2021 review only a couple of studies were found which have evaluated this approach(Larsen, 2021):
- An initial study with methodological concerns showed some promise in untrained lifters.
- A subsequent study that allowed trained lifters to choose the order of hypertrophy, strength, and power sessions throughout a week did not show benefit compared to a set order of hypertrophy -> power -> strength.
Overall, there is not enough research to fully evaluate the merits of this approach.
Tip: FNLP may be an excellent tool for people who struggle with motivation and consistency. On days where you do not feel like following your workout program you can choose a different workout to still be productive. For example, if your heart isn’t into lifting one day you can consider doing a cardio and jumping workout. If you really don’t feel like doing squats for whatever reason you can substitute a different exercise such as step-ups or lunges. If you feel completely worn down and need an extra day off then so be it, but if you feel you can actually do something productive then this approach allows you to make it happen. Any approach that allows greater consistency is likely worth considering.
Rating of perceived exertion (“RPE”)
RPE gauges the difficulty & exertion level of a set. This has been shown to be a valid and useful metric for a variety of different aerobic and resistance training modalities when assessing overall exercise intensity and physiological exertion.(Lea, 2022) Here I will discuss it particularly as it pertains to performing resistance training sets.
If you base RPE solely on exertion it may not correlate well with proximity to failure. For example, a high rep set of squats will frequently take more effort & exertion than a high rep set of dumbbell curls, even if both are taken to the same proximity to failure. However, if desired you can directly correlate RPE with proximity to failure (RIR-based RPE). This notion was initially published several years ago(Zourdos, 2016) and is widely used, at times with modifications. I have modified the initial version into the below table that makes slightly more sense to me conceptually:
Despite widespread use, there is ambiguity in the literature due to different potential definitions of RPE.(Halperin, 2020) Various terminology exists (ie, “effort” vs “exertion”, which are used identically or with distinct definitions based on the source). As discussed in Lesson 4 different definitions of failure are used as well, including:
- attempting and failing to complete an additional rep
- not attempting to complete an additional rep when you believe that you would not be able to complete it
- stopping a set when no further reps can be completed with consistent form even if further reps could be completed with form breakdown
Additionally, when people take sets to failure they do not necessarily assign a RPE of 10. Some literature observes RPE values as low as 7 with failure sets.(Helms, 2020) Other literature notes people tend to assign higher RPE values to higher rep failure sets than lower rep failure sets.(Steele, 2017) This may indicate that for many people RPE reflects discomfort, rather than exertion, as higher rep sets are typically more uncomfortable.
Note: Given these limitations, it is possible some people will benefit more from using RPE than others. If a person typically assigns higher RPE due to a set becoming uncomfortable (typical with higher rep compound sets) this may be a less viable approach. Nonetheless, many people use RPE to good effect, and the method of autoregulation with it is simple; instead of aiming to perform X amount of reps during a set, rather you aim to perform as many reps as possible until you reach a pre-assigned RPE value. Thus, on days you feel stronger you will perform more reps and on days you feel weaker you will perform fewer reps.
Example: Let’s say you are following a program where you want to take sets to a RPE of 8 in the 8-10 rep range. For illustrative purposes I will only include 1 set per session. The first 6 sessions may proceed as follows:
- Session 1: 100 pounds x 8 reps to a RPE of 8. You are within your desired range so you will keep the weight the same.
- Session 2: 100 x 9 to a RPE of 8. You are still within your desired range so you will keep the weight the same.
- Session 3: 100 x 9 to a RPE of 8. This is the same as last time. Thus, you will keep the weigh the same.
- Session 4: 100 x 10 to a RPE of 8. You are at the top end of the range but still within it; you will keep the weight the same.
- Session 5: 100 x 11 to a RPE of 8. You are beyond your desired rep range. Now you can increase the weight.
- Session 6: 105 x 8 to a RPE of 8. Now you start this same progression scheme with a higher weight.
There is no need to panic after session 3 above when no progress is demonstrated; if you are beyond the linear progression stage you should expect some sessions where you do not add weight or reps to your sets.
Repetitions in reserve (“RIR”)
When you take a set to failure you are by definition taking the set to a RIR = 0. This is easy to define but in practice is potentially inaccurate if you underestimate your lifting ability. In theory you may think you are at failure when in reality you could complete another rep if you were to try. Thus, the utility of using RIR depends on your ability to accurately assign a RIR value to each set. I have included some studies evaluating this below:
- When attempting to pick a weight with the goal of reaching failure at a specific number of reps, people of all experience levels underestimate the repetitions they can perform in a variety of different exercises.(Steele, 2017). Individuals with more experience are more accurate (within 1-2 reps vs ≥3 reps for beginners). Thus, it is difficult to know a priori how many reps you will achieve, particularly if you are a beginner.
- When estimating RIR during a set instead of prior to a set, one study evaluated the 10-20 rep range in the bench press and leg press.(Hackett, 2018) Subjects were accurate within 3 reps of their RIR prediction at the 10 rep mark. On most sets the accuracy averaged within 2 reps. The only set where the average accuracy was 3 reps was the first set of leg press in the first training session. In the subsequent session this improved to 2 reps. Males were generally more accurate than females. Interestingly, correlations between estimated RIR and actual RIR were between r = 0.59-0.87, while correlations between RPE and actual RIR were generally less than r = 0.5 and at times less than r = 0.2. This further shows RPE does not necessarily correlate well with RIR.
- A subsequent study by the same research group as the last study found fairly similar results (accuracy within ~1 rep with the chest press and 2-3 reps with the leg press).(Hackett, 2019) The authors noted that the accuracy of RIR prediction did not correlate well with perceptual fatigue (r = -0.26 for the chest press and r = -0.18 for the leg press).
- In an informative 2021 study the subjects maxed out on the squat and then took 70% of their 1RM (one rep max) to failure while attempting to estimate when they were at 5, 3, and 1 RIR.(Zourdos, 2021) Of note, they were not told the weight they were lifting. Therefore, any intuition regarding expected rep count from prior experience lifting that weight was unavailable. These were all male lifters with at least 2 years of experience performing squats. The sets ranged from 9-26 reps and individuals who were able to perform more reps were less accurate at the 5 RIR and the 3 RIR predictions. Regardless of total rep count accuracy was similar at the 1 RIR prediction. On average predictions were off by 5.15 reps at the 5 RIR prediction, 3.65 reps at the 3 RIR prediction, and 2.05 reps at the 1 RIR prediction.
Note: A key finding in the above study is the very wide discrepancy in the number of reps that could be performed with 70% of one’s 1RM. After all, a range of 9-26 is very large. This is one reason I do not favor non-autoregulated approaches that prescribe specific numbers of reps at a specific % of one’s 1RM; this approach can yield very different training effects between different people. This was further demonstrated in a study published in 1990; you can look at that study and examine Tables 3 and 4 to see the wide variability in the number of reps performed by untrained and trained male and female participants at 40%, 60% and 80% of their 1RM.(Hoeger, 1990)
Having said that, a separate 2021 study indicates two factors that can contribute to this wide discrepancy.(Hernández-Belmonte, 2021) One factor is an individual’s baseline level of strength; stronger individuals relative to their body weight were able to perform more reps at a given % of their 1RM. A second factor is the daily variation that may occur with your performance. For example, suppose you know your 1RM from prior testing is 100 pounds. If your program suggests you lift 70% of this, that would be 70 pounds. However, suppose any given day your actual 1RM can fluctuate from 90-105 pounds. Then 70 pounds may be anywhere from 67%-78% of your 1RM for that day. This can lead to a wide disparity in the number of reps you perform.
When controlling for those two factors in this study the largest range in squat reps obtained at 65% of one’s 1RM was 8 and the largest range at 75% of one’s 1RM was 5, much smaller than the 17 seen in the aforementioned study.
- In 2021 a scoping review and meta-analysis evaluating 12 studies found on average individuals undepredicted by ~1 rep, with accuracy generally decreasing more significantly when sets reached ≥12 reps and when predictions were made further from failure.(Halperin, 2021)
Tip: As seen above RIR is less accurate with higher rep sets and when staying further away from failure. In Lesson 5 I discussed that when performing higher rep sets staying to a RIR closer to 0-2 may be more beneficial to achieve the full benefits of the set. At an estimated RIR = 2 accuracy may be off by 2-3 reps, meaning you may be at an actual RIR = 5. If you continuously use higher rep sets and stay at a real RIR = 5 these sets may not be very valuable. For this reason, it is worthwhile to take higher rep sets to failure if you can safely do this every now and then to better understand what a real RIR = 0, 1, and 2 feels like. You can then “anchor” subsequent RIR estimations based on this feeling and this should improve accuracy.
Example: Let’s say you are following a program where you want to take sets to a RIR = 2-3 in the 8-10 rep range. For illustrative purposes I will only include 1 set per session. The first 6 sessions may proceed as follows:
- Session 1: 100 pounds x 8 reps to a RIR = 3. You are within your desired ranges so you will maintain the same weight.
- Session 2: 100 x 9 to a RIR = 2. You are still within your desired ranges so you will maintain the same weight again.
- Session 3: 100 x 9 to a RIR = 3. You are now stronger but still within your desired ranges so you will maintain the same weight.
- Session 4: 100 x 10 to a RIR =2. You are at the top of your rep range but not your RIR range so you will maintain the same weight.
- Session 5: 100 x 10 to a RIR = 3. You are now at the top of both your rep and your RIR range so you can increase the weight.
- Session 6: 105 x 8 to a RIR = 3. Now you start over this same progression scheme with a higher weight.
You don’t actually demonstrate increases in strength between sessions 1 & 2 as in both sessions you expect you could have performed 11 reps. This also applies to sessions 3 & 4 where you expect you could have performed 12 reps in each session. However, by going to a RIR = 2 instead of 3 the set may have been slightly more beneficial if you were underestimating your true RIR. Regardless, you do not expect strength to increase every session as you are beyond the linear progression stage.
Velocity-based training (“VBT”)
VBT is a newer method of employing autoregulation with much of the research being published in the last few years. The basic idea is:
- perform the concentric portion of each rep as fast as possible
- monitor the speed of each rep in a set
- stop a set once a repetition falls below a certain speed:
- this can be an absolute speed (ie, 0.6 meters per second)
- this can be a relative speed (ie, 20% slower than the first rep in the set)
You can generate a load-velocity profile (“LVP”) for a specific exercise. This LVP correlates repetition speed with a given percentage of your 1RM.(McBurnie, 2019) An individualized LVP is superior to a group-based LVP due to differences between lifters.(Balsalobre-Fernández, 2021) There are several different methods available to develop a program utilizing VBT.(Weakley, 2021a) Unfortunately, employing VBT as is commonly prescribed requires specialized equipment. There are many options out there but the more accurate ones are more expensive.(Weakley, 2021b) However, there is research showing that it is possible for individuals with prior training to relatively accurately perceive changes in repetition speed throughout a set, at least with the bench press and squat.(Sindiani, 2020)
The collective research indicates taking a set to a velocity loss of ~20% yields gains in strength, power, and hypertrophy; this corresponds to performing ~50% of your maximal reps in a set.(Hickmott, 2022; Zhang, 2023) Greater hypertrophy gains are seen by going to ~40% velocity loss but this may compromise neuromuscular adaptations; this corresponds to taking a set close to failure.(Pareja-Blanco, 2020) A 2022 analysis indicates you should likely include at least 3 minutes rest between sets to help maximize repetition speed, use full range of motion, and if your goal is to improve athleticism you should stick to higher velocity movements (meaning starting with a relatively low percentage of your maximum).(Baena-Marín, 2022)
A recent review discussed ways to combine velocity loss thresholds with RIR to overcome some of the individual variability in VBT.(Pelland, 2022) This variability can lead to different LVPs for different exercises, set-to-set variation, and different thresholds for specific RIRs between different people. Given this variability it may be difficult to generate programs and generalized advice that is applicable to everyone. The authors propose initial testing to determine specific velocity ranges that correspond to each individual RIR, and then using the velocity loss in a specific set to determine when a specific RIR is reached. One caveat is that the the studies used to determine this framework used relatively long inter-set rest periods (ie, 5 minutes); it remains to be seen if this approach will be useful in general and specifically with shorter repst periods.
Perhaps as time goes on the accelerometers and linear position transducers utilized with VBT will become more affordable (or better mobile apps will be created for this purpose); if this occurs this will be a more viable method of autoregulation for lifters of all experience levels. At this point though this is not going to be a practical option for most people, and thus I will not discuss it in more detail.
Using autoregulation to guide progression
As indicated above there are multiple methods you can use to autoregulate your programming, ranging from how to pick what to do in a specific session to how much effort to exert in a specific set. The key here is that when your body is ready to showcase improvement (by allowing more weight or more reps to be performed with a similar level of effort or exertion), this will be evident. This is very different from linear progression described above where more weight or reps are done every workout regardless of how you feel. Once linear progression is exhausted, a well-designed autoregulated approach makes it obvious when you can add more weight or reps to an exercise.
Considering the methods listed above, RPE and RIR are the most widely-used. RIR-based RPE makes them mostly equivalent, but keep in mind the studies above that indicate RPE and RIR do not always correlate well. They can also have separate nuances and potential drawbacks:
- RPE: typically higher with higher rep sets and with compound exercises, may reflect effort vs exertion vs discomfort and is subjective
- RIR: theoretically objective but practically can be inaccurate, seemingly more accurate as you approach failure and gain experience
Thus, given their distinctions, if you use them equivalently as RIR-based RPE you will lose any independent information you could obtain by tracking them distinctly. Nonetheless, many do this with good results. Regardless, as long as you understand how these two metrics interact and what influences them you can move forward with using either or both options in various scenarios.
Tip: Do not fall into the trap of trying to “force” progression when using an autoregulated approach. Remember, if you are beyond the linear progression stage you are not going to seem stronger every single workout. If at some point you don’t make any progress for several weeks in a row, and you are not yet an advanced lifter, consider the following problems:
- lack of consistency
- poor sleep
- poor nutrition or inadequate calories
- increased stress levels
If none of these are a significant factor then it is likely time to change your training program. The one caveat is if you are purposefully in a caloric deficit to lose weight; in this situation it may be more reasonable to set a goal of maintaining your current strength rather than gaining strength.
There is actually a lot of confusion in the literature regarding what constitutes periodization. Almost all would likely agree in a broad sense that periodization is considered an approach where training variables are varied over time. A 2021 review proposes the following universal definition(Kataoka, 2021):
In this section I will go through the underlying theory of periodization, brief examples, an overview of the literature, and then a summary for clarity.
Underlying theory of periodization
There are several ideas behind the concept of periodization:
- Avoid excess fatigue: By doing the same thing repeatedly too much fatigue may set in and you may experience diminishing returns. By planning out variation well, and including “deload” phases at strategic points (recall from Lesson 4 a deload phase entails decreasing training volume and possibly intensity to allow you to recover more fully from built up fatigue), you can avoid accumulating too much fatigue which would otherwise hinder results.
- Potentiate subsequent training: The variation should be planned out such that prior training develops fitness attributes that contribute to subsequent training. For example, starting a training block with significant cardiovascular work will increase your overall level of conditioning. In a subsequent training block you can use this increased fitness to focus on developing sport-specific skills without becoming fatigued to the point where you need to cut sessions short.
- In the world of sports where a year-long training plan is designed around a series of competitions, another aspect of periodization is to design the training program to help peak for competition(s).
Note: There are two underlying conceptual models by which periodization can make sense. These are:
- Supercompensation model: a theory that with intense training you “deplete” the body’s resources and then with adequate rest/recovery the body restores these resources to levels beyond the initial starting point. At this point you are more fit and have experienced a beneficial training effect.
- This can indeed occur with glycogen; by following a low-carbohydrate diet and performing extensive aerobic training you can deplete your body’s glycogen stores and then if you consume high amounts of carbohydrates your body will synthesize more glycogen (temporarily) than was present initially.(Murray, 2018)
- Besides glycogen there are no other bodily substances where supercompensation is known to occur in this format.(Buckner, 2020)
- Hence, for many years now the theory of supercompensation has fallen out of favor. You may still see the term “supercompensate” used but this is just to reflect the process of improving over time, not the actual supercompensation model.
- Fitness-fatigue model: this is the more common model still used today.(Greig, 2020) The idea is that as you train you induce fatigue but you also experience beneficial adaptations that increase your overall fitness. On any given day your overall performance is a summation of your fitness + fatigue.
- After training extensively your fatigue may be high enough to mask your fitness and your performance may decrease.
- At this point you can deload for a certain period of time. When deloading both your fatigue and your fitness decrease in magnitude, but your fatigue decreases to a greater extent than your fitness.
- Thus, your overall performance increases as you deload.
- This is the theory behind tapering for a competition.
Note: The fitness-fatigue model ties in closely with the concepts of “overreaching” and “overtraining”.(Bell, 2020)
- Functional overreaching is essentially the same idea as increasing fatigue through training, then deloading, and ending up with an increase in overall performance.
- Non-functional overreaching occurs when the increased training stimulus is maintained too long; when deloading occurs a full or near-full recovery is observed but there is no overall improvement in performance.
- Overtraining, or “overtraining syndrome” (“OTS”), occurs if you go well beyond the point of nonfunctional overreaching. This can lead to decreases in performance for months as well as several negative health effects. Thankfully, this is incredibly rare from straightforward resistance and athletic training. In fact, it is so rare that a 2022 SR did not find any studies actually describing its occurrence.(Weakley, 2022) If you follow a reasonable exercise program and adjust accordingly when signs of excess fatigue set in the odds of you entering a state of true overtraining are very minimal.
Of interest, a lot of symptoms of OTS overlap with “relative energy deficiency in sport” (“RED-S”), which describes a host of physiologic effects that occur when your energy intake is too low relative to your energy expenditure.(Stellingwerff, 2021) Thus, if there is any concern for overtraining it is possible that increasing your caloric intake will “fix” the problem (as opposed to the problem being from legitimately training too much).
Tip: If you have an upcoming vacation or short period of time where you know you will not exercise regularly, you can take advantage of the functional overreaching principle above. Assuming your normal training has not already caused you to accumulate a significant amount of fatigue, you can increase your training volume the week before a vacation. Then after the vacation when you are fully rested and recovered you may be even stronger than before the vacation started. Powerlifters and strength athletes will regularly take 2-7 days off prior to a competition to good effect.(Travis, 2020) Obviously there are several variables and factors here, but this is a viable strategy.
Brief examples of programming for periodization
Generally, when looking up studies of periodization with regards to resistance training several different approaches will emerge, including linear periodization (“LP”), reverse linear periodization (“RLP”), block periodization (“BP”), and undulating periodization (“UP”). UP is frequently described as daily undulating periodization (“DUP”) or weekly/biweekly undulating periodization (“WUP”). As discussed in Lesson 4, BP incorporates planning out different microcycles and mesocycles to train different attributes over the course of a macrocyle, with the goal being to maintain newly attained fitness attributes in subsequent training blocks. Thus, this approach makes more sense for athletes planning out a year of training but is not generally applied to individuals doing resistance training for the sole purpose of benefiting health, hypertrophy, and strength (though it could be done for individuals who want to train multiple different fitness attributes throughout a year).
The table below (also shown in Lesson 4) gives a brief example illustrating the difference between LP, RLP, and DUP. Each cell has sets x reps (3×10-12 means 3 sets of 10-12 reps).
LP schemes decrease the rep range throughout a mesocycle prior to resetting. RLP schemes do the opposite. With UP the rep ranges change throughout the week(s) and then reset. A deload week can be included prior to resetting (in the example above this would be included after week 4, some would do the above 4 week training block twice and then include a deload week after week 8).
Note: One method of UP has recently been described as the set-repetition best (“SRB”) method.(Suchomel, 2021) This helps account for the fact described above that different people can perform different amounts of reps with a given % of their 1RM. The idea here is to determine the maximum weight that you can use for different set and rep ranges (this is your SRB for that specific set & rep combination, ie, 3*3 maximum weight, 3*5 maximum weight, 5*10 maximum weight, etc). The programming prescription is then provided based on this (ie, perform 3*5 using 90% of your 3*5 SRB).
Thus far the studies cited in the above review utilize this and prescribe combinations of heavier and lighter days. This seems to yield good results, likely due to the inherent variability of rep ranges while also allowing for consistent effort between different rep ranges. In theory this can be used in an autoregulatory manner; based on the RPE or RIR of a given session’s sets you can adjust your estimated SRB for the subsequent session.
An example of BP may include the following four blocks in 4-week increments:
- Develop muscular endurance and general conditioning with higher repetition resistance training and shorter rest times.
- Focus on muscular hypertrophy and continue conditioning work once weekly.
- Emphasize muscular strength by working towards sets of 1-3 reps. Continue incorporating higher rep sets throughout the week and conditioning work at least once weekly.
- Prioritize speed and power. Continue to incorporate a few heavy sets (2-4 rep range) weekly to maintain maximal strength, incorporate higher rep volume work to maintain hypertrophy, and include conditioning work at least once weekly.
With this example general conditioning is initially developed and then de-emphasized but retained in subsequent training blocks. The same is then done with muscular hypertrophy and muscular strength in the following training blocks. After 16 weeks you could repeat the cycle, but instead of purely focusing on conditioning you could include aspects of the hypertrophy, strength, and power/speed blocks to help maintain those attributes.
Overview of recent literature regarding periodization
There is actually a lot of controversy regarding the utility of periodization. If curious, I have included an overview of recent, relevant review articles in the box below. You can skip this and read the below summary for the main practical points.
- A 2017 SR/MA evaluated periodized vs non-periodized approaches for muscular strength.(Williams, 2017) This included 18 studies and found a small-to-moderate positive effect of periodization for strength gains, particularly when participants were untrained and when using an UP model.
- A 2018 SR evaluated periodized vs non-periodized approaches for muscle hypertrophy.(Grgic, 2018) This included 12 studies of mostly untrained subjects and found no benefit of periodized approaches.
- A 2018 review of periodization and its impact on strength and hypertrophy noted that there is little overall research suggesting a strong benefit of periodization.(Fisher, 2018) It seems many studies are highly variable and too short in duration to yield any conclusions over longer time periods. Additionally, many of the studies do not adequately evaluate the impact of variety in exercise selection, detraining periods, and supervision. The authors note much of non-periodized programming still has sufficient variation to lead to adaptations.
- A 2019 review examined the literature evaluating periodization’s impact on strength and hypertrophy.(Evans, 2019) The author notes that meta-analyses generally have favored UP > LP for strength gains. However, some of the studies showing a benefit of periodization for strength used higher loads closer to the testing day; it is possible the better results are simply due to increased neuromuscular efficiency from lifting heavier weights and if non-periodized groups also lifted heavier weights there would not be a benefit to periodization. The author notes many of the studies evaluating hypertrophy have been too short to see significant differences. Additionally, studies comparing UP and LP protocols for hypertrophy primarily used strength-oriented programs with hypertrophy measured as a secondary outcome; the results of these studies are equivocal. Lastly, most of the studies to date have not incorporated deloading periods.
- A 2019 SR of MAs regarding periodized vs. non-periodized approaches included only 2 MAs and evaluated the 21 independent studies that comprised these MAs.(Alfonso, 2019) The authors found that none of the studies compared periodized approaches to non-periodized, varied approaches. Additionally, none of the studies utilized predictions concerning the timing of adaptations (meaning none were looking for a potentiation effect). Overall the authors concluded that the research still has a long way to go and it’s unclear if any benefits from periodization are simply due to the built in variation as opposed to the actual periodization structure.
- A 2020 review of periodization included many of the above findings, noting many of the studies of periodized vs non-periodized programs are <16 weeks duration, benefits for strength may come from the training specificity of the program rather than periodization itself, and the subset of studies that do show a benefit for hypertrophy often utilize indirect measures of lean body mass.(Buckner, 2020) The authors noted that eliciting true overtraining in humans with resistance training is difficult and the idea that variation is necessary for continued adaptation as you become more trained lacks physiologic support. The authors actually advocate using a flexible nonlinear periodization approach to manage fatigue by simply decreasing the training component(s) that is/are contributing the most to fatigue if excess fatigue accumulates.
- In a 2021 review (by the same group as the last review mentioned above) the authors noted that there have been >80 definitions of periodization proposed over the years, there is lots of confusion regarding the difference between “programming” and “periodization”, and the vast majority of studies are on too short of a time scale to actually evaluate periodization.(Kataoka, 2021) Additionally, the vast majority of studies do not consider other stress in an athlete’s life or peaking for a competition. Thus, almost all of the studies evaluate different methods of programming but do not actually evaluate periodization over a longer time scale.
- A 2021 narrative review on periodization and specifically BP discussed the history of periodization as well as the controversy in the literature regarding its application and terminology.(Stone, 2021) The authors noted that while evidence is sparse it does indicate that residual effects of one training block are sustainable and can potentiate a subsequent training phase. They also review studies including well-trained subjects or athletes and all of them find BP to be neutral or favorable towards outcomes compared to other training schemes. They note that planning functional overreaching likely works better for more advanced athletes. Ultimately they note that BP can be viewed as an integral part of traditional periodization. For example:
- An initial “accumulation” block may consist of work developing power and strength attributes.
- A subsequent “transmutation” block may consist of work developing more sport-specific power attributes.
- A final “realization” block may consist of event-specific technique work with a penultimate functional overreaching week followed by a week-long taper.
- Then all of this can be repeated, allowing the fully cycle to repeat multiple times as in traditional periodization.
- A 2022 SR/MA included 35 studies and found that periodization programs seemed to produce a slightly superior increase in maximal strength relative to non-periodization programs, with no benefit to hypertrophy.(Moesgaard, 2022) UP was beneficial relative to LP for maximal strength (with no benefit to hypertrophy) when only looking at studies including people with at least 6 months experience in resistance training. There were insufficient studies for other comparisons of different types of periodization.
Summary of periodization
In summary, periodization is a much talked about topic and is discussed frequently in the fitness and athletics world but there is very little research evaluating it adequately. Much of the discussion of “periodization” is actually a discussion of distinct conceptual points, such as:
- training variation throughout a year
- deloading or tapering for a competition
- programming microcycles or mesocycles over a shorter time period
For individuals in sports who want to peak for separate competitions, or for individuals who want to focus on different training attributes at different time points, periodization seems like a viable strategy. For individuals simply training for general health, strength, hypertrophy, or conditioning, there is no strong evidence that periodization with distinct focuses on different attributes over a year-long time period will prove more beneficial than incorporating training for all attributes simultaneously.
When it comes to the specific programming aspects (ie, LP vs RLP vs UP), even though they have “periodization” in their name they actually are more accurately described as “programming”. Regardless, there is no strong evidence that any one of these approaches is greater than the others, and there is no strong evidence that any of these are greater than traditional resistance training programming that includes sufficient variability. At the same time, there is no evidence that these programming approaches or periodization in general are inferior training strategies. There are many intermediate & advanced resistance training and overall athletic programs that utilize these strategies sensibly, and many people get great results with them.
Thus, periodization is an excellent option for individuals who want to incorporate a greater amount of variety in their training, but for the average individual looking to improve overall health and fitness it is by no means necessary.
When you first begins training it is generally easy to make progress; a reasonable program and consistency will go a long way. In this initial phase it is logical to follow a simple linear progression scheme while developing good technique and building desirable habits. Eventually linear progression comes to an end and then adjustments need to be made. This generally entails autoregulation of some sort, and while there are multiple methods available these more recently tend to incorporate RPE or RIR. Following a lifting routine set up with the parameters discussed in Lesson 5 while incorporating RPE or RIR to guide set termination will allow you to continue making progress for a very long time. If you would like to incorporate greater variety, train different fitness attributes at different time points, or prepare for a specific competition, incorporating periodization is a viable strategy.
Now I have discussed much of the theoretical aspects of resistance training. In the next two lessons I will do the same for aerobic training.
Click here to proceed to Lesson 7
- Afonso J, Rocha T, Nikolaidis PT, Clemente FM, Rosemann T, Knechtle B. A Systematic Review of Meta-Analyses Comparing Periodized and Non-periodized Exercise Programs: Why We Should Go Back to Original Research. Front Physiol. 2019 Aug 7;10:1023. doi: 10.3389/fphys.2019.01023. PMID: 31440169; PMCID: PMC6692867.
- Baena-Marín M, Rojas-Jaramillo A, González-Santamaría J, Rodríguez-Rosell D, Petro JL, Kreider RB, Bonilla DA. Velocity-Based Resistance Training on 1-RM, Jump and Sprint Performance: A Systematic Review of Clinical Trials. Sports (Basel). 2022 Jan 4;10(1):8. doi: 10.3390/sports10010008. PMID: 35050973; PMCID: PMC8822898.
- Balsalobre-Fernández C, Muñoz-López M, Marchante D, García-Ramos A. Repetitions in Reserve and Rate of Perceived Exertion Increase the Prediction Capabilities of the Load-Velocity Relationship. J Strength Cond Res. 2021 Mar 1;35(3):724-730. doi: 10.1519/JSC.0000000000002818. PMID: 30312197.
- Bell L, Ruddock A, Maden-Wilkinson T, Rogerson D. Overreaching and overtraining in strength sports and resistance training: A scoping review. J Sports Sci. 2020 Aug;38(16):1897-1912. doi: 10.1080/02640414.2020.1763077. Epub 2020 Jun 30. PMID: 32602418.
- Buckner SL, Jessee MB, Mouser JG, Dankel SJ, Mattocks KT, Bell ZW, Abe T, Loenneke JP. The Basics of Training for Muscle Size and Strength: A Brief Review on the Theory. Med Sci Sports Exerc. 2020 Mar;52(3):645-653. doi: 10.1249/MSS.0000000000002171. PMID: 31652235.
- Damas F, Libardi CA, Ugrinowitsch C. The development of skeletal muscle hypertrophy through resistance training: the role of muscle damage and muscle protein synthesis. Eur J Appl Physiol. 2018 Mar;118(3):485-500. doi: 10.1007/s00421-017-3792-9. Epub 2017 Dec 27. PMID: 29282529.4
- Evans JW. Periodized Resistance Training for Enhancing Skeletal Muscle Hypertrophy and Strength: A Mini-Review. Front Physiol. 2019 Jan 23;10:13. doi: 10.3389/fphys.2019.00013. PMID: 30728780; PMCID: PMC6351492.
- Fisher J, Steele J, Smith D, Gentil P. Periodization for optimizing strength and hypertrophy; the forgotten variables. Journal of Trainology. 2018;7:10-15. doi: 10.17338/trainology.7.1_10.
- Greig L, Stephens Hemingway BH, Aspe RR, Cooper K, Comfort P, Swinton PA. Autoregulation in Resistance Training: Addressing the Inconsistencies. Sports Med. 2020 Nov;50(11):1873-1887. doi: 10.1007/s40279-020-01330-8. PMID: 32813181; PMCID: PMC7575491.
- Grgic J, Lazinica B, Mikulic P, Schoenfeld B. Should resistance training programs aimed at muscular hypertrophy be periodized? A systematic review of periodized versus non-periodized approaches. Science & Sports. 2018;33(3):e97-e104. doi: 10.1016/j.scispo.2017.09.005.
- Hackett DA, Cobley SP, Halaki M. Estimation of Repetitions to Failure for Monitoring Resistance Exercise Intensity: Building a Case for Application. J Strength Cond Res. 2018 May;32(5):1352-1359. doi: 10.1519/JSC.0000000000002419. PMID: 29337829.
- Hackett DA, Selvanayagam VS, Halaki M, Cobley SP. Associations between Perceptual Fatigue and Accuracy of Estimated Repetitions to Failure during Resistance Exercises. J Funct Morphol Kinesiol. 2019 Aug 9;4(3):56. doi: 10.3390/jfmk4030056. PMID: 33467371; PMCID: PMC7739315.
- Halperin I, Emanuel A. Rating of Perceived Effort: Methodological Concerns and Future Directions. Sports Med. 2020 Apr;50(4):679-687. doi: 10.1007/s40279-019-01229-z. PMID: 31745731.
- Halperin I, Malleron T, Har-Nir I, Androulakis-Korakakis P, Wolf M, Fisher J, Steele J. Accuracy in Predicting Repetitions to Task Failure in Resistance Exercise: A Scoping Review and Exploratory Meta-analysis. Sports Med. 2021 Sep 20. doi: 10.1007/s40279-021-01559-x. Epub ahead of print. PMID: 34542869.
- Helms ER, Kwan K, Sousa CA, Cronin JB, Storey AG, Zourdos MC. Methods for Regulating and Monitoring Resistance Training. J Hum Kinet. 2020 Aug 31;74:23-42. doi: 10.2478/hukin-2020-0011. PMID: 33312273; PMCID: PMC7706636.
- Hernández-Belmonte A, Courel-Ibáñez J, Conesa-Ros E, Martínez-Cava A, Pallarés JG. Level of Effort: A Reliable and Practical Alternative to the Velocity-Based Approach for Monitoring Resistance Training. J Strength Cond Res. 2021 May 20. doi: 10.1519/JSC.0000000000004060. Epub ahead of print. PMID: 34027915.
- Hickmott LM, Chilibeck PD, Shaw KA, Butcher SJ. The Effect of Load and Volume Autoregulation on Muscular Strength and Hypertrophy: A Systematic Review and Meta-Analysis. Sports Med Open. 2022 Jan 15;8(1):9. doi: 10.1186/s40798-021-00404-9. PMID: 35038063; PMCID: PMC8762534.
- Hoeger, Werner W.K.1; Hopkins, David R.2; Barette, Sandra L.3; Hale, Douglas F.3 Relationship between Repetitions and Selected percentages of One Repetition Maximum, Journal of Strength and Conditioning Research: May 1990 – Volume 4 – Issue 2 – p 47-54
- Kataoka R, Vasenina E, Loenneke J, Buckner SL. Periodization: Variation in the Definition and Discrepancies in Study Design. Sports Med. 2021 Apr;51(4):625-651. doi: 10.1007/s40279-020-01414-5. Epub 2021 Jan 6. PMID: 33405190.
- Larsen S, Kristiansen E, van den Tillaar R. Effects of subjective and objective autoregulation methods for intensity and volume on enhancing maximal strength during resistance-training interventions: a systematic review. PeerJ. 2021 Jan 12;9:e10663. doi: 10.7717/peerj.10663. PMID: 33520457; PMCID: PMC7810043.
- Lea JWD, O’Driscoll JM, Hulbert S, Scales J, Wiles JD. Convergent Validity of Ratings of Perceived Exertion During Resistance Exercise in Healthy Participants: A Systematic Review and Meta-Analysis. Sports Med Open. 2022 Jan 8;8(1):2. doi: 10.1186/s40798-021-00386-8. PMID: 35000021.
- McBurnie A, Allen K, Garry M, Martin M, Thomas D, Jones P, Comfort P, McMahon J. The Benefits and Limitations of Predicting One Repetition Maximum Using the Load-Velocity Relationship. Strength and Conditioning Journal. 2019 Dec;41(6):28-40. doi: 10.1519/SSC.0000000000000496
- Moesgaard L, Beck MM, Christiansen L, Aagaard P, Lundbye-Jensen J. Effects of Periodization on Strength and Muscle Hypertrophy in Volume-Equated Resistance Training Programs: A Systematic Review and Meta-analysis. Sports Med. 2022 Jan 19. doi: 10.1007/s40279-021-01636-1. Epub ahead of print. PMID: 35044672.
- Murray B, Rosenbloom C. Fundamentals of glycogen metabolism for coaches and athletes. Nutr Rev. 2018 Apr 1;76(4):243-259. doi: 10.1093/nutrit/nuy001. PMID: 29444266; PMCID: PMC6019055.
- Pareja-Blanco F, Alcazar J, SÁnchez-ValdepeÑas J, Cornejo-Daza PJ, Piqueras-Sanchiz F, Mora-Vela R, SÁnchez-Moreno M, Bachero-Mena B, Ortega-Becerra M, Alegre LM. Velocity Loss as a Critical Variable Determining the Adaptations to Strength Training. Med Sci Sports Exerc. 2020 Aug;52(8):1752-1762. doi: 10.1249/MSS.0000000000002295. PMID: 32049887.
- Pelland JC, Robinson ZP, Remmert JF, Cerminaro RM, Benitez B, John TA, Helms ER, Zourdos MC. Methods for Controlling and Reporting Resistance Training Proximity to Failure: Current Issues and Future Directions. Sports Med. 2022 Mar 5. doi: 10.1007/s40279-022-01667-2. Epub ahead of print. PMID: 35247203.
- Sindiani M, Lazarus A, Iacono AD, Halperin I. Perception of changes in bar velocity in resistance training: Accuracy levels within and between exercises. Physiol Behav. 2020 Oct 1;224:113025. doi: 10.1016/j.physbeh.2020.113025. Epub 2020 Jun 23. PMID: 32585167.
- Steele J, Endres A, Fisher J, Gentil P, Giessing J. Ability to predict repetitions to momentary failure is not perfectly accurate, though improves with resistance training experience. PeerJ. 2017 Nov 30;5:e4105. doi: 10.7717/peerj.4105. PMID: 29204323; PMCID: PMC5712461.
- Stellingwerff T, Heikura IA, Meeusen R, Bermon S, Seiler S, Mountjoy ML, Burke LM. Overtraining Syndrome (OTS) and Relative Energy Deficiency in Sport (RED-S): Shared Pathways, Symptoms and Complexities. Sports Med. 2021 Nov;51(11):2251-2280. doi: 10.1007/s40279-021-01491-0. Epub 2021 Jun 28. PMID: 34181189.
- Stone MH, Hornsby WG, Haff GG, Fry AC, Suarez DG, Liu J, Gonzalez-Rave JM, Pierce KC. Periodization and Block Periodization in Sports: Emphasis on Strength-Power Training-A Provocative and Challenging Narrative. J Strength Cond Res. 2021 Aug 1;35(8):2351-2371. doi: 10.1519/JSC.0000000000004050. PMID: 34132223.
- Suchomel TJ, Nimphius S, Bellon CR, Hornsby WG, Stone MH. Training for Muscular Strength: Methods for Monitoring and Adjusting Training Intensity. Sports Med. 2021 Oct;51(10):2051-2066. doi: 10.1007/s40279-021-01488-9. Epub 2021 Jun 8. PMID: 34101157.
- Travis SK, Mujika I, Gentles JA, Stone MH, Bazyler CD. Tapering and Peaking Maximal Strength for Powerlifting Performance: A Review. Sports (Basel). 2020 Sep 9;8(9):125. doi: 10.3390/sports8090125. PMID: 32917000; PMCID: PMC7552788.
- Weakley J, Mann B, Banyard H, McLaren S, Scott T, García Ramos A. Velocity-Based Training: From Theory to Application. Strength and conditioning journal. 2021a Apr;43(2):31-49. doi: 10.1519/SSC.0000000000000560
- Weakley J, Morrison M, García-Ramos A, Johnston R, James L, Cole MH. The Validity and Reliability of Commercially Available Resistance Training Monitoring Devices: A Systematic Review. Sports Med. 2021b Mar;51(3):443-502. doi: 10.1007/s40279-020-01382-w. Epub 2021b Jan 21. PMID: 33475985; PMCID: PMC7900050.
- Weakley J, Halson SL, Mujika I. Overtraining Syndrome Symptoms and Diagnosis in Athletes: Where Is the Research? A Systematic Review. Int J Sports Physiol Perform. 2022 May 1;17(5):675-681. doi: 10.1123/ijspp.2021-0448. Epub 2022 Mar 23. PMID: 35320774.
- Williams TD, Tolusso DV, Fedewa MV, Esco MR. Comparison of Periodized and Non-Periodized Resistance Training on Maximal Strength: A Meta-Analysis. Sports Med. 2017 Oct;47(10):2083-2100. doi: 10.1007/s40279-017-0734-y. PMID: 28497285.
- Zhang X, Li H, Bi S, Luo Y, Cao Y, Zhang G. Auto-Regulation Method vs. Fixed-Loading Method in Maximum Strength Training for Athletes: A Systematic Review and Meta-Analysis. Front Physiol. 2021 Mar 12;12:651112. doi: 10.3389/fphys.2021.651112. PMID: 33776802; PMCID: PMC7994759.
- Zhang X, Feng S, Li H. The Effect of Velocity Loss on Strength Development and Related Training Efficiency: A Dose-Response Meta-Analysis. Healthcare (Basel). 2023 Jan 23;11(3):337. doi: 10.3390/healthcare11030337. PMID: 36766912; PMCID: PMC9914552.
- Zourdos MC, Klemp A, Dolan C, Quiles JM, Schau KA, Jo E, Helms E, Esgro B, Duncan S, Garcia Merino S, Blanco R. Novel Resistance Training-Specific Rating of Perceived Exertion Scale Measuring Repetitions in Reserve. J Strength Cond Res. 2016 Jan;30(1):267-75. doi: 10.1519/JSC.0000000000001049. PMID: 26049792.
- Zourdos MC, Goldsmith JA, Helms ER, Trepeck C, Halle JL, Mendez KM, Cooke DM, Haischer MH, Sousa CA, Klemp A, Byrnes RK. Proximity to Failure and Total Repetitions Performed in a Set Influences Accuracy of Intraset Repetitions in Reserve-Based Rating of Perceived Exertion. J Strength Cond Res. 2021 Feb 1;35(Suppl 1):S158-S165. doi: 10.1519/JSC.0000000000002995. PMID: 30747900.